The present invention relates in general to an electrical heating apparatus for removing vaporizable impurities from lubricating oil and, more particularly, to a unit of this type which is generally similar to that shown in U.S. Pat. No. 2,219,101, granted Oct. 22, 1940 to Nelson J. Finwall. The vaporizing unit of the Finwall patent has disadvantages which the present invention overcomes.
More particularly, the lubricating oil to be heated by the element 41 of Finwall is intended to be deposited thereon by the conduit 51, which terminates directly above the heating element. However, I have found that, in actual practice, the conduit 51 deposits the lubricating oil on the smaller upper end of the conical spiral heating element 41 throughout only a narrow range of operating temperatures. More particularly, when the lubricating oil is cold, it tends to flow to the left under the discharge end of the conduit 51 and dribbles downwardly onto only a part of the heating element 41, or misses it completely. On the other hand, when the oil is hot, it partially or completely overshoots the heating element. Thus, the lubricating oil is properly delivered to the heating element throughout only a narrow intermediate temperature range. Even under such conditions, distribution of the lubricating oil over the heating element is not uniform.
Because of the foregoing situation, one of the disadvantages of the Finwall unit is that the desired function of eliminating vaporizable impurities, such as water, gasoline, acids, and the like, is not carried out efficiently. Another disadvantage is that since there are numerous occasions wherein the heating element 41 is not completely wetted with the lubricating oil, carbonization of the lubricating oil frequently occurs over all or parts of the element, resulting in the formation of undesirable deposits which interfere with proper operation of the heating element, and which ultimately must be filtered out of the oil.